Ann: DataMotion wins defamation action , page-8

More info here:

http://www.artslaw.com.au/LegalInformation/Defamation/DefamationLawsAfterJan06.asp

Some important points (this isn't legal advice and I'm not a lawyer btw):

A corporation can't sue for defamation unless it has less than 10 employees.

I assume that a director or manager may be able to sue if the comments are of a personal nature, but there are many possible defences. "Truth" is the obvious one but possibly difficult to prove. "Fair comment" may be more relevant. You may have to show its a matter of public interest which shouldn't be difficult if its a public company and the comments are related to the company and not the individual's personal life:

"Honest Opinion (Fair Comment)
Previously referred to as the defence of fair comment, the defence of honest opinion requires you to prove that the material communicated was an expression of honest opinion rather than a statement of fact, on a matter of public interest and was based on proper material. To take advantage of this defence you have to be able to prove three things:

a. the communication must, on the face of it, be comment that is: an opinion, criticism, deduction, judgment, remark, observation, or conclusion;
b. the facts upon which the opinion is based must be stated unless they are widely known. This is required so that the readers/viewers/listeners are able to form their own views on the facts. These facts have to be known to you when you make the communication. It is very important that the comment is clearly distinguishable from the facts upon which it is based; and
c. the communication has to be on a matter of public interest.

The opinion can be extreme, as long as it is honestly held by the communicator. This means that you have to be very careful in responding to an initial complaint. If you say that you didnt mean it this could subsequently make it very difficult to raise the defence of honest opinion.

The defence of honest opinion is obviously very relevant for reviewers and critics, but it can also be useful for satirists, comedians and other artists whose work incorporates an element of social commentary."